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176 lines
4.9 KiB
Go
176 lines
4.9 KiB
Go
/*
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* Minio Go Library for Amazon S3 Compatible Cloud Storage
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* Copyright 2017 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package credentials
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import (
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"sync"
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"time"
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)
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// A Value is the AWS credentials value for individual credential fields.
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type Value struct {
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// AWS Access key ID
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AccessKeyID string
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// AWS Secret Access Key
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SecretAccessKey string
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// AWS Session Token
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SessionToken string
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// Signature Type.
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SignerType SignatureType
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}
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// A Provider is the interface for any component which will provide credentials
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// Value. A provider is required to manage its own Expired state, and what to
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// be expired means.
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type Provider interface {
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// Retrieve returns nil if it successfully retrieved the value.
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// Error is returned if the value were not obtainable, or empty.
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Retrieve() (Value, error)
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// IsExpired returns if the credentials are no longer valid, and need
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// to be retrieved.
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IsExpired() bool
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}
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// A Expiry provides shared expiration logic to be used by credentials
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// providers to implement expiry functionality.
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//
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// The best method to use this struct is as an anonymous field within the
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// provider's struct.
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//
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// Example:
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// type IAMCredentialProvider struct {
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// Expiry
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// ...
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// }
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type Expiry struct {
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// The date/time when to expire on
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expiration time.Time
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// If set will be used by IsExpired to determine the current time.
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// Defaults to time.Now if CurrentTime is not set.
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CurrentTime func() time.Time
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}
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// SetExpiration sets the expiration IsExpired will check when called.
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//
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// If window is greater than 0 the expiration time will be reduced by the
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// window value.
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//
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// Using a window is helpful to trigger credentials to expire sooner than
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// the expiration time given to ensure no requests are made with expired
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// tokens.
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func (e *Expiry) SetExpiration(expiration time.Time, window time.Duration) {
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e.expiration = expiration
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if window > 0 {
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e.expiration = e.expiration.Add(-window)
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}
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}
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// IsExpired returns if the credentials are expired.
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func (e *Expiry) IsExpired() bool {
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if e.CurrentTime == nil {
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e.CurrentTime = time.Now
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}
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return e.expiration.Before(e.CurrentTime())
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}
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// Credentials - A container for synchronous safe retrieval of credentials Value.
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// Credentials will cache the credentials value until they expire. Once the value
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// expires the next Get will attempt to retrieve valid credentials.
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//
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// Credentials is safe to use across multiple goroutines and will manage the
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// synchronous state so the Providers do not need to implement their own
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// synchronization.
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//
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// The first Credentials.Get() will always call Provider.Retrieve() to get the
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// first instance of the credentials Value. All calls to Get() after that
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// will return the cached credentials Value until IsExpired() returns true.
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type Credentials struct {
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sync.Mutex
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creds Value
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forceRefresh bool
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provider Provider
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}
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// New returns a pointer to a new Credentials with the provider set.
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func New(provider Provider) *Credentials {
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return &Credentials{
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provider: provider,
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forceRefresh: true,
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}
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}
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// Get returns the credentials value, or error if the credentials Value failed
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// to be retrieved.
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//
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// Will return the cached credentials Value if it has not expired. If the
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// credentials Value has expired the Provider's Retrieve() will be called
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// to refresh the credentials.
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//
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// If Credentials.Expire() was called the credentials Value will be force
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// expired, and the next call to Get() will cause them to be refreshed.
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func (c *Credentials) Get() (Value, error) {
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c.Lock()
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defer c.Unlock()
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if c.isExpired() {
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creds, err := c.provider.Retrieve()
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if err != nil {
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return Value{}, err
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}
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c.creds = creds
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c.forceRefresh = false
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}
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return c.creds, nil
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}
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// Expire expires the credentials and forces them to be retrieved on the
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// next call to Get().
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//
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// This will override the Provider's expired state, and force Credentials
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// to call the Provider's Retrieve().
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func (c *Credentials) Expire() {
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c.Lock()
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defer c.Unlock()
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c.forceRefresh = true
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}
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// IsExpired returns if the credentials are no longer valid, and need
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// to be refreshed.
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//
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// If the Credentials were forced to be expired with Expire() this will
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// reflect that override.
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func (c *Credentials) IsExpired() bool {
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c.Lock()
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defer c.Unlock()
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return c.isExpired()
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}
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// isExpired helper method wrapping the definition of expired credentials.
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func (c *Credentials) isExpired() bool {
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return c.forceRefresh || c.provider.IsExpired()
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}
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